Android imitates QQ5.0 side sliding interface effect based on ViewDragHelper

public class SlidingMenu extends FrameLayout {
 
 private ViewDragHelper mViewDragHelper;
 
 private int mHeight;// 当前控件的高度
 private int mWidhth;// 当前控件的宽度
 private int mRange; // 菜单移动的距离
 
 private ViewGroup mMenu;// 菜单内容
 private ViewGroup mContent; // 主页面内容
 
 private boolean isOpen = false;// 判断是否打开菜单
 
 public SlidingMenu(Context context) {
  this(context, null);
 }
 
 public SlidingMenu(Context context, AttributeSet attrs) {
  this(context, attrs, 0);
 }
 
 public SlidingMenu(Context context, AttributeSet attrs, int defStyleAttr) {
  super(context, attrs, defStyleAttr);
 
  // 初始化ViewDragHelper
  mViewDragHelper = ViewDragHelper.create(this, callback);
 }
}

<?xml version="1.0" encoding="utf-8"?>
<com.yitong.myslidingmenu2.view.SlidingMenu
 xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:tools="http://schemas.android.com/tools"
 android:id="@+id/main_slidingMenu"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:background="@mipmap/bg"
 android:orientation="horizontal"
 tools:context="com.yitong.myslidingmenu2.MainActivity">
 
 <include layout="@layout/left_menu"/>
 
 <LinearLayout
  android:id="@+id/main_content"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:background="@mipmap/qq"
  android:orientation="horizontal">
 
  <Button
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:onClick="click"
   android:text="切换菜单"/>
 
 </LinearLayout>
</com.yitong.myslidingmenu2.view.SlidingMenu>

@Override
protected void onFinishInflate() {
  super.onFinishInflate();
 
  if (getChildCount() < 2) {
   throw new IllegalStateException("使用SlidingMenu中必须包含两个View");
  }
  if (!(getChildAt(0) instanceof ViewGroup && getChildAt(1) instanceof ViewGroup)) {
   throw new IllegalStateException("子View必须是ViewGroup的子类");
  }
 
  mMenu = (ViewGroup) getChildAt(0);
  mContent = (ViewGroup) getChildAt(1);
 }
 
 @Override
 protected void onSizeChanged(int w, int h, int oldw, int oldh) {
  super.onSizeChanged(w, h, oldw, oldh);
  mHeight = getMeasuredHeight();
  mWidhth = getMeasuredWidth();
  mRange = (int) (mWidhth * 0.8);
 }

@Override
public boolean onInterceptHoverEvent(MotionEvent event) {
 // 把触摸事件传递给ViewDragHelper
 return mViewDragHelper.shouldInterceptTouchEvent(event);
}
 
@Override
public boolean onTouchEvent(MotionEvent event) {
 try {
  mViewDragHelper.processTouchEvent(event);// 让ViewDrageHelper处理触摸事件
 } catch (Exception e) {
  e.printStackTrace();
 }
 return true;
}

private Callback callback = new Callback() {
 
 @Override
 public boolean tryCaptureView(View child, int pointerId) {
  return true;// child：当前被拖拽的view.返回true表示当前view可以被拖拽
 }
 
 @Override
 public int getViewHorizontalDragRange(View child) {
  return mRange;// 返回拖拽的距离，并不对拖拽进行限制，决定了动画的执行速度
 }
 
 @Override
 public int clampViewPositionHorizontal(View child, int left, int dx) { // 根据建议值，修订水平方向移动的距离
  if (child == mContent) { // ①滑动主页面内容，当超过屏幕预留宽度时，不再滑动。②向左滑动不能为负
   left = fixContentSlidRange(left);
  }
  return left;
 }
 
 @Override
 public void onViewPositionChanged(View changedView, int left, int top, int dx, int dy) {// 当View的位置改变时调用，可以在此方法中添加一些View特效
  super.onViewPositionChanged(changedView, left, top, dx, dy);
  // 当我们滑动菜单内容时，保持菜单内容不动，转化为主页面内容移动
  int moveContentLeft = left;// 主页面内容左边的距离
  if (changedView == mMenu) {
   moveContentLeft = mContent.getLeft() + left;
   mMenu.layout(0, 0, mMenu.getHeight(), mMenu.getHeight());// 强制菜单不移动
  }
  moveContentLeft = fixContentSlidRange(moveContentLeft);
  mContent.layout(moveContentLeft, 0, moveContentLeft + mContent.getWidth(), mContent.getHeight());
 
  animShow(moveContentLeft);// 菜单打开时，一些动画
 
  invalidate();// 重绘界面，兼容低版本
 }
 
 @Override
 public void onViewReleased(View releasedChild, float xvel, float yvel) {// 当view松手时触发，处理自动平滑动画
  super.onViewReleased(releasedChild, xvel, yvel);
  if (xvel > 0) { // 水平速度+
   open();
  } else if (xvel == 0 && mContent.getLeft() > mRange / 2.0f) { // 手指在菜单滑出一半多时抬起
   open();
  } else {
   close();
  }
 }
};
 
 /**
 * 修订主页面的滑动距离
 */
 private int fixContentSlidRange(int left) {
  if (left > mRange) {
   return mRange;
  } else if (left < 0) {
   return 0;
  }
  return left;
 }
 
/** 伴随动画 */
private void animShow(int moveContentLeft) {
 float percent = moveContentLeft * 1.0f / mRange;// 0~1
 
 /**
  * 分析：
  *  菜单区域：位移动画，缩放动画，渐变动画
  *  内容区域：缩放动画
  *  背景区域：亮度变化
  */
 ViewHelper.setTranslationX(mMenu, evaluate(percent, -mRange / 1.2f, 0));// 位移动画
 ViewHelper.setScaleX(mMenu, evaluate(percent, 0.6f, 1.0f));// 缩放动画
 ViewHelper.setScaleY(mMenu, evaluate(percent, 0.6f, 1.0f));
 ViewHelper.setAlpha(mMenu, evaluate(percent, 0.1f, 1.0f));// 渐变动画
 
 ViewHelper.setPivotX(mContent, 0);// 缩放中心
 ViewHelper.setPivotY(mContent, mHeight / 2);
 ViewHelper.setScaleX(mContent, evaluate(percent, 1.0f, 0.9f));// 缩放动画
 ViewHelper.setScaleY(mContent, evaluate(percent, 1.0f, 0.9f));
 
 getBackground().setColorFilter((Integer)(colorEvaluate(percent, Color.BLACK, Color.TRANSPARENT)), PorterDuff.Mode.SRC_OVER);// 亮度变化
}
 
/** 估值器，根据开始数字和结束数字，随着百分比的变化得到一个数值，详情见FloatEvaluator */
 private Float evaluate(float fraction, Number startValue, Number endValue) {
  float startFloat = startValue.floatValue();
  return startFloat + fraction * (endValue.floatValue() - startFloat);
 }
 
 /** 颜色取值，根据初始颜色和结束颜色，随着百分的变化取出不同的颜色，详情见ArgbEvaluator */
 private Object colorEvaluate(float fraction, Object startValue, Object endValue) {
  int startInt = (Integer) startValue;
  int startA = (startInt >> 24) & 0xff;
  int startR = (startInt >> 16) & 0xff;
  int startG = (startInt >> 8) & 0xff;
  int startB = startInt & 0xff;
 
  int endInt = (Integer) endValue;
  int endA = (endInt >> 24) & 0xff;
  int endR = (endInt >> 16) & 0xff;
  int endG = (endInt >> 8) & 0xff;
  int endB = endInt & 0xff;
 
  return (int)((startA + (int)(fraction * (endA - startA))) << 24) |
    (int)((startR + (int)(fraction * (endR - startR))) << 16) |
    (int)((startG + (int)(fraction * (endG - startG))) << 8) |
    (int)((startB + (int)(fraction * (endB - startB))));
 }

/** 菜单切换 */
public void toggle() {
 if(isOpen) {
  close();
 } else {
  open();
 }
}
 
/**
* 打开菜单
*/
private void open() {
 if (mViewDragHelper.smoothSlideViewTo(mContent, mRange, 0)) {// 判断主页面是否滑动到指定位置
  ViewCompat.postInvalidateOnAnimation(this);// 会触发computeScroll
 }
 isOpen = true;
}
 
/**
* 关闭菜单
*/
private void close() {
 if (mViewDragHelper.smoothSlideViewTo(mContent, 0, 0)) {// 判断主页面是否滑动到指定位置
  ViewCompat.postInvalidateOnAnimation(this);// 会触发computeScroll
 }
 isOpen = false;
}
 
@Override
public void computeScroll() {
 super.computeScroll();
 if (mViewDragHelper.continueSettling(true)) {// 持续执行动画，如果返回则表示动画还没有执行完
  ViewCompat.postInvalidateOnAnimation(this);
 }
}

public class MainActivity extends Activity {
 
 private SlidingMenu mSlidingMenu;
 
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  requestWindowFeature(Window.FEATURE_NO_TITLE);
  setContentView(R.layout.activity_main);
  initView();
 }
 
 private void initView() {
  mSlidingMenu = (SlidingMenu) findViewById(R.id.main_slidingMenu);
 }
 
 public void click(View view) {
  mSlidingMenu.toggle();
 }
}